Straw for the preservation of a predetermined dose of liquid-based substance, in particular pure or diluted animal semen; and set comprising it

ABSTRACT

The invention relates to a straw comprising a tube ( 11 ) and a gas-permeable and liquid-tight stopper ( 12 ), said stopper ( 12 ) being arranged in the tube ( 11 ), close to an end ( 16 ). The invention is characterised in that the stopper ( 12 ) comprises an indicator component ( 20 ) having a first pre-determined colour in the absence of previous contact with said substance ( 21 ) and a second pre-determined colour, of a different shade from that of the first colour, once it has been in contact with said substance ( 21 ). The assembly comprises the straw ( 10 ) and a device ( 26 ) for controlling the filling of the straw.

The invention generally relates to the preservation of a predetermineddose of liquid-based substance, in particular pure or diluted animalsemen; and more particularly to the straws for performing suchpreservation.

It is known that such a straw comprises a tube and a stopper disposed inthe tube. The stopper is usually of the three-part type originallydescribed in French patent 995 878, corresponding to British patent 669265, i.e. formed by two plugs made from a fibrous substance enclosing apowder which, on contact with a liquid, transforms into an impermeablepaste or gel adhering to the wall of the tube so that the stopper isliquid-tight.

Similar but improved stoppers are described by the French patentapplications 2 824 255 and 2 824 256.

Stoppers of another type are also known, for example a stopper made froma single-piece cylinder of hydrophobic microporous material described byEuropean patent application 0 873 726 or a stopper made from asingle-piece cylinder of sintered self-sealing microporous material asdescribed by PCT application WO 2010/070533.

In the initial state, the stopper is disposed in the neighborhood of oneof the ends of the tube and it is provided that in the filled state, thedose of liquid substance which must be preserved in the straw isdisposed between the stopper and the other end of the tube (the endfurthest from the stopper). The tube and the stopper are configured forthe stopper to be able to slide in the tube towards the end that isinitially furthest from the stopper.

To fill the straw, the end closest to the stopper is placed incommunication with a vacuum source while the furthest end of the tube isplaced in communication with a vessel containing the substance to beintroduced into the straw.

The air initially contained between the stopper and the furthest end ofthe tube is sucked through the stopper while the substance moves forwardinto the tube until it meets the stopper.

If necessary, after filling, the straw is welded close to one or both ofits ends and is stored cold.

In order to empty the straw, if necessary after cutting the welded endportions and thawing, a rod is inserted into the tube via the endclosest to the stopper, until it bears against the stopper. Using thisrod, the plug is made to slide in the manner of a piston towards the endfurthest from the stopper, which causes the expulsion of the dose ofsubstance which had been introduced into the straw.

The invention is directed to making it possible to detect, simply,conveniently and economically, whether the straw has been correctlyfilled.

To that end the invention provides a straw for the preservation of apredetermined dose of liquid-based substance, comprising a tube and agas- permeable liquid-tight stopper, which stopper is disposed in thetube in the neighborhood of one end, characterized in that: said stoppercomprises an indicator component having a first predetermined color inthe absence of prior contact with said substance and a secondpredetermined color, having a hue different from the hue of the firstcolor, when it has been in contact with said substance.

It is recalled here that the hue of a color corresponds to thewavelengths (or to the single wavelength in the case of a color of therainbow) of the light emitted by the object having that color. The hueis only one of the components of the color, which depends on otherparameters such as luminosity and saturation.

Conventional three-part stoppers for straws maintain the same hue whenthe straw is in the empty state and the filled state. The dry or mattaspect of the powder of the stopper when the straw is in the empty stateand the moist or satin aspect of the paste or gel of the stopper whenthe straw is an the filled state are linked to the other parameters ofcolor.

The indicator component comprised by stopper of the straw according tothe invention makes it possible to know whether the stopper has been incontact with the substance to preserve in the straw, by determiningwhether the indicator component has taken on the hue of the secondcolor.

Such determination is particularly simple to perform, visually by anoperator or automatically.

The implementation of the straw according to the invention and of thedetection of the proper filling thereof is furthermore feasible in aparticularly simple and economical manner, in particular as set outbelow.

According to advantageous features:

-   -   said indicator component emits light of which the spectrum        comprises at least one peak having a crest of predetermined        wavelength when it has been in contact with said substance and        does not comprise said peak in the absence of prior contact with        said substance;    -   said indicator component emits light of which the spectrum        comprises said at least one peak in response to illumination by        light comprising a predetermined range of wavelengths that is        offset relative to the predetermined wavelength of said crest;    -   said stopper is formed by two plugs made from a fibrous        substance enclosing a sealing agent formed by a powder        transforming on contact with said substance into an impermeable        paste or gel adhering to the wall of the tube so that the        stopper is liquid-tight, said indicator component comprising        said sealing agent;    -   said powder comprises a powder of a salt that is non-fluorophore        in the dry state and fluorophore when it is dissolved in water;    -   said salt forms part of the group comprising a fluorescein salt,        a Rhodamine B salt, a Rhodamine 6G salt and a salt of        Eriochrome® Cyanine R;    -   said powder comprises between 1/100 and 1/100000 by weight of        said salt powder;    -   said powder is formed by said salt powder and by powder of        material that polymerizes on contact with water;    -   said powder of material that polymerizes on contact with water        is alginate;    -   said indicator component having a first predetermined color in        the absence of prior contact with said substance and a second        predetermined color, having a hue different from the first color        hue, when it has been in contact with said substance; and/or    -   said stopper is formed by two plugs made from a braided fibrous        substance enclosing a sealing agent formed by a powder which, on        contact with a liquid, transforms into an impermeable paste or        gel adhering to the wall of the tube so that the stopper is        liquid-tight, at least one of the two plugs comprising said        indicator thread.

The invention is also directed to a set comprising a straw as set forthabove and a device for checking filling of said straw, characterized inthat said checking device comprises a detection member for detectingwhether said indicator component has taken on said hue of the secondcolor.

According to advantageous features:

-   -   said indicator component of the stopper of the straw emits light        of which the spectrum comprises at least one peak having a crest        of predetermined wavelength when the indicator component has        been in contact with said substance and does not comprise said        peak in the absence of prior contact with said substance; and        said detection member comprised by the checking device is        configured to detect the absence from or the presence in the        spectrum formed by the light emitted by said indicator        component, of said at least one peak;    -   said indicator component of the stopper of the straw emits light        of which the spectrum comprises said at least one peak in        response to illumination by light comprising a predetermined        range of wavelengths that is offset relative to the        predetermined wavelength of said crest; and said checking device        further comprises an illuminating member to illuminate said        indicator component by light comprising said predetermined range        of wavelengths; and/or    -   the checking device forms part of a filler machine for straws        and comprises a processing unit linked to a detection member        configured to emit a stop signal for the filler machine if the        detection member detects a straw in which the indicator        component has not taken on said hue of the second color.

The disclosure of the invention will now be continued with thedescription of embodiments, given below given below by way ofnon-limiting example, with reference to the attached drawings, in which:

FIG. 1 is a diagrammatic view in longitudinal section of a strawaccording to the invention, in the empty state;

FIG. 2 is a view similar to FIG. 1 but showing the straw in the filledstate;

FIG. 3 is a graph illustrating the spectrum of the light emitted by afluorophore agent comprised by the stopper of the plug when the straw isin the filled state;

FIG. 4 is a similar view to FIG. 2 but showing the straw in a machinecomprising a device for checking filling of the straw;

FIG. 5 is a view similar to FIG. 4 but showing a variant of the devicefor checking filling of the straw; and

FIG. 6 is a similar view to FIG. 3 but for a variant of the fluorophoreagent.

The straw 10 illustrated in FIG. 1 comprises a tube 11 and a stopper 12.

The tube 11 is conventionally made from extruded plastic material, heretransparent, with an inside diameter for example of 1.6 or 2.5 mm and alength of the order of 133 mm.

The stopper 12 is of the three-part type, i.e. formed by two plugs 13and 14 made from a fibrous substance enclosing a sealing agent 20 formedby a powder (FIG. 1) which, on contact with a liquid, is capable oftransforming into an impermeable paste or gel 15′ (FIG. 2) adhering tothe wall of the tube 11 so that the stopper 12 is liquid-tight.

In the initial state, shown in FIG. 1, the stopper 12 is disposed in theneighborhood of the end 16 of the tube 11 and it is provided that in thefilled state, the dose of liquid-based substance which must be preservedin the straw 10 is disposed between the stopper 12 and the end 17 of thetube 11 that is the furthest from the stopper 12.

In order to fill the straw 10, the end 16 is placed in communicationwith a vacuum source while the end 17 is placed in communication with avessel containing the substance to be introduced into the straw.

The air initially contained between the stopper 12 and the end 17 issucked through the stopper 12 while the substance 21 (FIG. 2) movesforward in the tube 11 until it encounters the stopper 12, by the end 18thereof that is turned towards the end 17 of the tube 11, that is to saythe end of the stopper 12 that can be seen on the right in FIGS. 1 and2.

The straw 10 is then in the filled state shown in FIG. 2.

If necessary, after filling, the straw is welded in the neighborhood ofone or both of its ends 16 and 17 and is placed in cold storage.

To empty the straw 10, if necessary after cutting the welded endportions and thawing, there is inserted into the tube 11 a rod whichcomes to bear on the end 19 of the stopper 12 (which end is situated onthe opposite side to the end 18).

Using this rod, the stopper 12 is made to slide in the manner of apiston towards the end 17 or the end which corresponds after cutting thewelded portion, which causes the expulsion of the dose of substance 21which had been introduced into the straw.

On comparing FIGS. 1 and 2, it will be noted that the stopper 12 has adifferent aspect when the straw 10 is in the empty state (FIG. 1) andthe filled state (FIG. 2).

When the straw 10 is in the empty state, the sealing agent 20 (powder15) of the stopper 12 is of a first color and when the straw 10 is inthe filled state, the sealing agent 20 (gel 15′) is of a second color.

Here, the hue of the first color (empty state) is brownish white whilethe hue of the second color (filled state) is greenish yellow.

For example, the powder 15, as seen through tube 11, is of Pantone® 155Ucolor and the gel 15′, as seen through the tube 11, is of Pantone® 395Ccolor.

It is recalled here that the hue of a color corresponds to thewavelengths (or to the single wavelength in the case of a color of therainbow) of the light emitted by the object having that color. The hueis only one of the components of the color, which depends on otherparameters such as luminosity and saturation.

The change in hue between the powder 15 and the gel 15′ is due to thepresence, in the sealing agent 20, of a product changing hue between thedry state and the state dissolved in water.

Here, the product changing color is the sodium salt of fluorescein.

It will be noted that the fluorescein sodium salt is not spermicidal andtherefore is suitable for contact with animal semen.

It is known that the fluorescein sodium salt has the following formula:

and that it is identified by the number CAS 518-47-8.

It is also known that the fluorescein sodium salt is a fluorophore salti.e. capable of emitting fluorescent light when it is dissolved inwater; while in the dry state it is a non-fluorophore salt.

When the sealing agent 20 of the stopper 12 is in the dry state (powder15) the fluorescein sodium salt does not emit fluorescent light since itis in the dry state. When the sealing agent 20 of the stopper 12 is inthe dampened state (gel 15′), the fluorescein sodium salt is dissolvedin the water contained in the gel 15′ and then emits fluorescent light.

The change in hue of the sealing agent 20 is due to the addition offluorescent light.

By virtue of the presence of the fluorescein sodium salt, the sealingagent 20 forms an indicator component indicating contact between thestopper 12 and the substance 21: the sealing agent 20 is of apredetermined color in the absence of prior contact with the substance21 and a second predetermined color, having a different hue to the hueof the first color, when the sealing agent 20 has been in contact withthe substance 21.

It will be observed, as illustrated in FIG. 2, that in the dampenedstate of the stopper 12, part of the plug 13 has taken on the same hueas the gel 15′.

As a matter of fact, on filling the straw, between the moment when thesubstance 21 reached the powder 15 and the moment when the powder 15transformed into a liquid-tight gel 15′, a small quantity of powder 15dissolved by the substance 21 but not yet gelled was absorbed by theplug 13.

The indicator component indicating contact with the substance 21, formedby the sealing agent, is useful for checking the proper filling of thestraw 10, and more precisely the proper dampening of the stopper 12 bythe substance 21.

It is known that it is very important, for the proper preservation ofthe substance 21 contained in the straw 10, that the stopper 12 becorrectly dampened. As a matter of fact, in a case in which the straw 10is not welded at its ends, or welded only at the end 17 furthest fromthe stopper 12, the fluid-tightness of the straw 10 is ensured in partby the stopper 12.

On emptying the straw 10, the correct dampening of the stopper 12 onfilling enables the stopper 12 to play its piston role without therebeing leaks between the tube 11 and the stopper 12.

Checking the proper filling of the straw can be carried out visually bythe operator, simply by verifying that the sealing agent 20 of thestopper 12 has indeed adopted the hue of the second predetermined color,i.e. a greenish yellow hue in the present example.

The proper filling of the straw 10 can also be checked automatically, aswill be explained below.

FIG. 3 is a graph illustrating the spectrum of the light emitted by thefluorescein sodium salt when it is dissolved in water, i.e. thefluorophore agent contained by the gel 15′. In the graph of FIG. 3, thewavelengths in nm are along the abscissa axis and the relative intensityof the emission is along the ordinate axis.

It can be seen that the fluorescein sodium salt in the state dissolvedin water emits light of which the spectrum comprises a peak 22 having acrest 23 the wavelength of which is of the order of 520 nm, whichcorresponds to the aforementioned greenish yellow hue; and that the peakis relatively narrow, which it typical of light from fluorescence.

The light emitted by the sealing agent 20 in the dampened state (gel15′) has a broader spectrum but also comprises a peak 22 having a crest23.

In the spectrum, the apex of the peak 22 situated in the neighborhood ofthe crest 23 is clearly distinct from the rest of the spectrum and maythus be relatively easily identified by an automatic device.

FIG. 4 shows a machine 25 for filling straws comprising a device 26 forchecking filling of the straws 10 filled by the machine 25.

The checking device 26 comprises a member 27 for detecting whether theindicator component 20 has taken on the hue of the second color, that isto say the hue of the gel 15′.

Here, the detection member 27 comprises an electronic photoreceptormember and a member for electronic analysis of the information providedby the photoreceptor member to determine whether the spectrum of thelight received by the photoreceptor member comprises the apex of thepeak 22 situated in the neighborhood of the crest 23.

In addition to the detection member 27, the checking device 26 comprisesa processing unit 28 linked to the detection member 27 and configured toemit a stop signal for the filling machine 25 in case the detectionmember 27 detects a straw 10 in which the indicator component 20 has nottaken on the hue of the second color.

When the stop signal is emitted, the filling machine 25 stops.

An operator may then identify the reasons for the improper filling ofthe straw and solve the problem which may have occurred.

It will be noted that in the dry state, the fluorescein sodium salt ishydrophilic. It thus dissolves practically instantaneously in contactwith the liquid-based substance 21 which comprises a high proportion ofwater. Therefore, the reaction time of the indicator componentindicating contact formed by the sealing agent 20 is particularly brief.

By virtue of this high reaction speed, the filling device 26 may bedisposed in the machine 25 at a filler station and practicallyinstantaneously detect a filling defect of the straw.

By stopping the filler machine, the number of mis-filled straws isminimized, which is very important since in general the substance topreserve in a straw has a high economic value.

The fast reaction time enables the checking of the filling to beimplemented including in machines with a high operating rate, capable offilling up to several thousand straws per hour.

The device for checking filling 26 shown in FIG. 4 is capable ofoperating in ambient light.

In the variant shown in FIG. 5, which is useful in particular in thesituations in which the ambient light is insufficient, the checkingdevice 26 further comprises a lighting member 29 for the sealing agent20.

It is known that fluorescein sodium salt in the dissolved state in wateris mainly excited by a set of wavelengths situated in the neighborhoodof 495 nm, i.e. in a predetermined range of wavelengths that is offsetrelative to the wavelength of the crest 23 (520 nm).

The lighting member 29 emits light comprising that predetermined rangeof wavelengths.

It is advantageous, so as to avoid the lighting member 29 perturbing thedetection member 27, to configure the lighting member 29, by takingadvantage of the offset between the excitation wavelength and theemission wavelength so as not to emit light or in any event a minimum oflight in the emission range of wavelengths.

In the example illustrated of the stopper 12, the powder 15 comprises1/1000 by weight of fluorescein sodium salt powder in the dry state.

A range suitable for the implementation of the invention is from 1/100to 1/100000 by weight of fluorescein sodium salt powder in the drystate.

Advantageously, the range is from 1/500 to 1/50000, and still moreadvantageously from 1/1000 to 1/25000.

To obtain good homogeneity, the powder 15 is prepared by successivemixing operations.

In the illustrated example of the stopper 12, the powder 15 isexclusively formed by fluorescein sodium salt powder in the dry stateand by powder of material that polymerizes on contact with water.

Here, the powder of material that polymerizes on contact with water isalginate.

In a variant of the sealing agent 20, the fluorescein sodium salt powderin the dry state is replaced by another product that is not fluorophorein the dry state and is fluorophore when it is dissolved in water, whichis in the form of a salt in the dry state.

This is for example another fluorescein salt, a Rhodamine B salt, aRhodamine 6G salt and/or a salt of Eriochrome® Cyanine R.

It is known that Rhodamine B has the following formula:

and that it is identified by the number CAS 81-88-9.

It is known that Rhodamine 6G has the following formula:

and that it is identified by the number CAS 989-38-8.

It is known that Eriochrome® Cyanine R has the following formula;

and that it is identified by the number CAS 64-18-9.

FIG. 6 shows in the same way as FIG. 3 the light spectrum emitted by amixture of fluorescein, Rhodamine 6G and Rhodamine B.

This spectrum comprises a peak 35 having a crest 36 for Rhodamine 6G anda peak 37 having a crest 38 for Rhodamine B.

It can be seen that the crest 36 has a wavelength of the order of 553 nmand that the crest 38 has a wavelength of the order of 579 nm.

The fluorophore agent comprised by the sealing agent 20 in the dampenedstate (gel 15′) may be formed, as illustrated in FIG. 6, by a mixture offluorescein, Rhodamine 6G and Rhodamine B or by only one or by two ofthese products.

By selecting one or more of these products, the hue of the sealing agent20 in the dampened state (gel 15′) can be adjusted. The selection of thehue of the indicator component constituted by the sealing agent 20 whenit has been in contact with the substance, enables the straw 10 to berecognized, visually or by analysis of the light spectrum emitted, inparticular based on the location of the crest or crests such as 23, 36and 38, chosen so as not to be superposed.

In other variants, the agent modifying the color of the indicatorcomponent is a colorant, without being a fluorophore.

In such variants, the light emitted by the indicator component such asthe sealing agent 20 of the stopper 12 does not comprise a peak having acrest of predetermined wavelength when it has been in contact with thesubstance such as animal semen, but a relatively broad range ofwavelengths of the same intensity, which is less easy to detectautomatically.

The color-modifying agent being a colorant, without being a fluorophore,is for example methylene blue or α-zurine.

Such coloring products, when in the dry state, for example in the formof a small proportion of the sealing agent 20 in the dry state (powder15) do not affect or affect only a very little the color of the otherproducts forming the indicator component, for example the alginatepowder. On the other hand, when the indicator component is dampened, thecoloring product communicates its coloration to the rest of theindicator component, for example the gel 15′.

In variants not illustrated, the indicator component is different fromthe sealing agent 20, for example an indicator thread having, just asfor the sealing agent 20, a first predetermined color in the absence ofprior contact with the substance 21 and a second predetermined color,having a different hue from the hue of the first color, when it has beenin contact with the substance 21. Such an indicator thread is associatedwith the stopper 12 or with a stopper of different type, for example astopper made from a single piece cylinder as described in Europeanpatent application 0 873 726 or in PCT application WO 2010/070533.

The association of an indicator thread with the stopper 12 is made forexample, in the case in which the plug 13 or the plug 14 is a braid madefrom threads of fibrous substance, by incorporating the thread in thebraid. For example, the indicator thread is braided with the threads offibrous substance.

It is also possible to associate several indicator threads with thestopper 12.

For example, the indicator thread or threads are disposed in the centerof the buffer 14 and communicate their coloration to the rest of theplug 14 when it is dampened.

In another variant, the indicator component is formed both by thesealing agent 20 and by the indicator thread associated with the stopper12.

In other variants, the indicator component is different from the sealingagent and from a thread, for example a ball or a pellet integrated intothe stopper.

In other variants, the change in color of the indicator component 15 isbrought about on contact with a liquid other than water, for example aproduct contained in a diluent or a semen preservative for animal semen.

In other variants, the material of the tube such as 11 is nottransparent, but translucent, for example slightly colored; and thedetection takes into account the passage of the light emitted by theindicator component through the material of the tube such as 11.

Numerous other variants are possible according to circumstances, and inthis connection it is to be noted that the invention is not limited tothe examples described and shown.

1. A straw for the preservation of a predetermined dose of liquid-basedsubstance, comprising a tube (11) and a gas-permeable liquid-tightstopper (12), which stopper (12) is disposed in the tube (11) in theneighborhood of one end (16), which tube (11) and which stopper (12) areconfigured for the stopper (12) to be able to slide in the tube (11)towards the other end (17), wherein said stopper (12) comprises anindicator component (20) having a first predetermined color in theabsence of prior contact with said substance (21) and a secondpredetermined color, having a hue different from the hue of the firstcolor, when it has been in contact with said substance (21).
 2. A strawaccording to claim 1, wherein said indicator component (20) emits lightof which the spectrum comprises at least one peak (22, 35, 37) having acrest (23, 36, 38) of predetermined wavelength when it has been incontact with said substance and does not comprise said peak (22, 35, 37)in the absence of prior contact with said substance.
 3. A strawaccording to claim 2, wherein said indicator component (20) emits lightof which the spectrum comprises said at least one peak (22, 35, 37) inresponse to illumination by light comprising a predetermined range ofwavelengths that is offset relative to the predetermined wavelength ofsaid crest (23, 36, 38).
 4. A straw according to claim 1, wherein saidstopper (12) is formed by two plugs (13, 14) made from a fibroussubstance enclosing a sealing agent (20) formed by a powder (15)transforming on contact with said substance (21) into an impermeablepaste or gel (15′) adhering to the wall of the tube (11) so that thestopper (12) is liquid-tight, said indicator component comprising saidsealing agent (20).
 5. A straw according to claim 4, wherein said powder(15) comprises a powder of a salt that is non-fluorophore in the drystate and fluorophore when it is dissolved in water.
 6. A strawaccording to claim 5, wherein said salt forms part of the groupcomprising a fluorescein salt, a Rhodamine B salt, a Rhodamine 6G saltand a salt of Eriochrome® Cyanine R.
 7. A straw according to claim 5,wherein said powder (15) comprises between 1/100 and 1/100000 by weightof said salt powder.
 8. A straw according to claim 5, wherein saidpowder (15) is formed by said salt powder and by powder of material thatpolymerizes on contact with water.
 9. A straw according to claim 8,wherein said powder of material that polymerizes on contact with wateris alginate.
 10. A straw according to claim 1, wherein said indicatorcomponent comprises an indicator thread having a first predeterminedcolor in the absence of prior contact with said substance and a secondpredetermined color, having a hue different from the first color hue,when it has been in contact with said substance.
 11. A straw accordingto claim 10, wherein said stopper is formed by two plugs (13, 14) madefrom a braided fibrous substance enclosing a sealing agent (20) formedby a powder (15) which, on contact with a liquid, transforms into animpermeable paste or gel (15′) adhering to the wall of the tube so thatthe stopper is liquid-tight, at least one of the two plugs (13, 14)comprising said indicator thread.
 12. A set comprising a straw accordingto claim 1 and a device (26) for checking filling of said straw, whereinsaid checking device 26) comprises a detection member (27) for detectingwhether said indicator component (20) has taken on said hue of thesecond color.
 13. A set according to claim 12, wherein the indicatorcomponent (20) of the stopper (12) of the straw (10) emits light ofwhich the spectrum comprises at least one peak (22, 35, 37) having acrest (23, 36, 38) of predetermined wavelength when the indicatorcomponent (20) has been in contact with said substance (21) and does notcomprise said peak (22, 35, 37) in the absence of prior contact withsaid substance (21); and said detection member (27) comprised by thechecking device (26) is configured to detect the absence from or thepresence in the spectrum formed by the light emitted by said indicatorcomponent (20), of said at least one peak (22, 35, 37).
 14. A setaccording to claim 13, wherein said indicator component (20) of thestopper (12) of the straw (10) emits light of which the spectrumcomprises said at least one peak (22, 35, 37) in response toillumination by light comprising a predetermined range of wavelengthsthat is offset relative to the predetermined wavelength of said crest(23, 36, 38); and said checking device (26) further comprises anilluminating member (29) to illuminate said indicator component (20) bylight comprising said predetermined range of wavelengths.
 15. A setaccording to claim 12, wherein the checking device (26) forms part of afiller machine (25) for straws and comprises a processing unit (28)linked to a detection member (27) configured to emit a stop signal forthe filler machine (25) if the detection member (27) detects a straw(10) in which the indicator component (20) has not taken on said hue ofthe second color.